Hybrid vehicles are widely used in recent years due to societal demand requesting to improve fuel consumption and to reduce the exhaust gas. Such hybrid vehicles may include the engine and a motor as power sources. For example, the hybrid vehicles may improve the fuel consumption by operating EV-driving mode that moves the vehicle by the motor while stopping the engine. However, the fuel consumption tends to deteriorate in winter since a time period in which the engine is operated becomes longer to generate a required amount of heat required for a heating operation of the air conditioners. The amount of heat may be an amount of heat from the cooling water for the engine.
Patent Literature 1 discloses an air conditioner for a vehicle that mounts a heater, which is a heat source other than the engine, configured to heat the cooling water. The heater includes a heat pump and an exhaust-heat recovery device. The heater includes a heat pump and an exhaust-gas recovery device. A rotational speed of a compressor for the heat pump based on a temperature of the cooling water, a temperature of the exhaust gas, and a load applied to the engine. As a result, power consumption of the heat pump is reduced.